Thickness gauge

ABSTRACT

An inexpensive thickness gauge for measuring thickness through holes prepared for the installation of fasteners, or at an edge of sheet material to determine thickness of individual or stacked sheets for various purposes. The gauge is comprised of two major components constructed from thin sheet material which are so shaped and so move with respect to one another as to provide a novel device which provides magnified readings, durable construction, compactness, and direct reading in fastener grip dash numbers, wire gages, sheet metal gages, etc.

SUMMARY

This invention relates to thickness measuring devices and moreparticularly to devices which measure thickness through holes preparedfor the installation of fasteners, and at an edge of sheet material todetermine thickness of individual or stacked sheets for variouspurposes. The type of gauge to which the present invention is applicableis comprised of two major components constructed from sheet materialwhich are so shaped and so move with respect to one another as toprovide a novel device which is rugged, compact, easily read, and hasimproved overall accuracy of measurement over existing devices.

Measuring thickness of structure through holes or at edges so thatproper length fasteners may be selected for installation is a frequentrequirement during construction of aircraft, missiles, and the like. Inmany instances correct selection is critical. Existing gauges for thepurpose fall into three general categories: (1) Hook gauges sold byindividual fastener manufacturers, usually calibrated in approximately1/16 inch graduations they are difficult to read and provide littleaccuracy particularly when used through countersunk holes for gripmeasurement. (2) Micrometer head with hook anvil. These are expensiveand bulky and difficult and slow to use. They require the gauge readingto be converted to fastener grip dash number by use of a conversionchart. (3) Dial indicators. They are expensive, fragile, and alsorequire conversion of reading.

Hook gauges are calibrated only for the fastener they were designed for.By their nature they can contain only two scalesone on each side of thehook. Most different fasteners have different grip increments andstarting points. For example, the following aerospace fasteners arecited: NAS1398D6-1 has a grip range of 0.032-0.062". NAS1919BO4-01 is0.025-0.062". NAS1921BO4-01 is 0.057-MS90353-06-01 is 0.031-0.095". Thelast dash number in all cases is the grip dash number. It can be seenthat a special gage is needed for most different fastener types.

In view of the shortcomings of existing devices for the purpose, it isan object of this invention to provide an inexpensive, compact, durablegauge which is high accuracy, is easily read in production shop or fieldservice use, reads, fastener grip number directly, and has the capacityto handle a variety of grip scales on one gauge. It is another object ofthis invention to provide the capacity for various gauge configurationswithin the framework of the basic gauge which can satisfy a variety ofUser's special requirements. These include but are not limited to,multiple scales on the same gauge (including fastener grip numberscales, metric or inch fractional or decimal scales, scales not relatedto fastener grip selection, etc.), varying degrees of scalemagnification, multiple hook gauges, etc.

DESCRIPTION OF INVENTION

The invention resides in the relative motion of one gauge component withrespect to the other so as to magnify the reading for ease of use andincreased accuracy, the use of the body of the gauge for placement ofthe scale thus permitting multiple scales on the same gauge, the use ofthe body of the gauge as a perpendicular reference point, theconstruction of the gauge minimize cost, and the shape of the gaugewhich permits great accuracy in a novel way while maintaining compactsize and the capacity to suit the requirements of a variety of uses.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a side elevational view of a single hook gauge employing onemeasureing scale.

FIG. 2 is a similar view of a double hook gauge with additionalmeasuring capacity.

FIG. 3 is a similar view of a double hook gauge with two different scalemagnifications.

FIG. 4 is a similar view showing the reverse side of the gauge of FIG. 1except that an additional component allows additional scales to beutilized.

FIG. 1 is an elevational view of the basic gauge embodying the presentinvention. Frame (1) with integral scale (3) and slot (4) is fitted withslide (2) having integral hook (6), providing a close sliding fitbetween the two major components throughout the slot length. Both theframe and slide are constructed from sheet material nominally 0.030"thick. The angle of the slot (4) with respect to surface (5) determinesthe amount of scale magnification with respect to the grip measuringmotion of hook (6). In practive, the gauge is held between the thumb andforefinger and extended toward maximum grip. The hook is engaged at thebottom of material thickness to be measured and the slide is moved untilit fetches up. The gauge can be read in place or removed and read. FIG.1 depicts a gauge with a 30 degree angle of slot yielding a two-timesscale magnification. (Sine 30 is 0.5) The gauge depicted is shown atapproximately two times actual size and is intended primarily formeasuring material thickness of sheet metal for rivet installation, andhas a total grip range of from zero to 10/16 inches. The grip range ofthe gauge depicted may be increased by selecting an increased angleduring construction (at the expense of reduced scale magnification), byincreasing the size of the gauge, or by use of interchangeable slideswith longer hooks.

FIG. 2 is an elevational view of a gauge configuration providingextending grip range without sacrificing scale magnification. Frame 1ahaving integral scales 3a and 4a of equal linear dimension, and slot 5a,is fitted with slide 2a having integral hooks 6a and 7a of differentlengths so that scale 3a and hook 6a provide extended grip measuringcapability. Surface 8a and 9a are parallel so that a chosen slot anglewill provide the same scale magnification for scale 3a and 4a. The gaugedepicted will measure from zero to 10/16" using scale 4a and hook 7a,and from 11/16" to 20/16" using scale 3a and hook 6a.

FIG. 3 is an elevational view of a gauge configuration providing twohooks, one yielding exaggerated scale magnification while the other lessmagnified scale. Frame 1b, having integral scales 3b and 4b of unequallinear dimension, and slot 5b, is fitted with slide 2b having integralhooks 6b and 7b of different lengths. Surfaces 8b and 9b are notparallel. The angle of slot 5b with respect to these surfaces isselected during construction to provide desired scale magnification andgrip range. The gauge depicted has a slot angle of 14.5 degrees withrespect to surface 9b and measures zero through 6/16" with a scalemagnification of 4 times. Angle of slot with respect to surface 8b canbe varied during construction to achieve desired measuringcharacteristics. The gauge depicted measurers zero through 20/16" at aslight scale magnification using scale 3b and hook 6b.

FIG. 4 is an elevational view of the reverse side of FIG. 1 showing thatby the addition of indicator (7), fastened through slot (4) to slide (2)in a manner permitting both to slide together the length of the slot,additional scales of different linear dimension may be utilized toincrease versatility of the gauge. Indicator (7) is constructed fromsheet material nominally 0.030" thick. Reference edge (8) is used toread the scales.

I claim:
 1. A gauge having two members one moveable relative to theother and having a straight edge portion thereon, a straight scale onsaid member having the straight edge portion, and at an angle to saidstraight edge, the other member having at least one gauge portionmoveable at an angle relative to said straight scale wherein relativemovement between the members indicates on the gauge the relativedistance between the straight edge portion and the gauge portion.
 2. Agauge having a first component and another component which areslideably, moveably connected to one another, wherein said firstcomponent has a straight scale thereon and wherein said other componentslides relative to the first component, the sliding movement of thefirst component relative to the other component being at an angle to thestraight scale on the first component, the other component having agauge end portion extending beyond said first component which gauge endportion approaches said first component when said other component slidesrelative to the first component in one direction and which othercomponent also has a scale portion displaced from said gauge end portionwhich cooperates with said straight scale to indicate the relativedistance between the gauge end portion and the first component.